Cylinder lock structure

Abstract

Structure for locking a cylinder piston or the like in one limiting position thereof including a housing, a wedge member secured to the piston for reciprocation therewith mounted within the housing and having a cam surface thereon, and a locking piston positioned within the housing for reciprocal movement transversely of the wedge member also having a cam surface thereon engageable with the cam surface of the wedge member in one position thereof to secure the cylinder piston in the one limiting position. The camming surfaces have a surface area and a locking angle with respect to the cylinder piston to provide improved locking force on the cylinder piston and prevent backup of the cylinder piston on pressure drop or failure to the locking piston.

What I claim as my invention is: 
     
       1. In combination, a cylinder, a cylinder piston positioned within the cylinder for axial movement therein between a first and a second position, said cylinder piston including a piston rod connected thereto movable axially of the cylinder and a locking structure for releasably locking the piston in its first position, said locking structure comprising a housing, means for securing the housing to the cylinder, said housing having a first opening therethrough axially aligned with the piston rod when the housing is secured to the cylinder, a second opening through said housing extending transversely of the axis of the cylinder, means for passing an actuating medium into and out of the second opening of said housing, a cylindrical wedge member having a transverse slot extending approximately halfway through one side thereof, one side of which is a cam surface inclined with respect to the axis of the cylinder, means for securing the wedge member to the piston rod as an axial extension thereof, means for preventing rotation of said wedge member, a solid, cylindrical locking piston positioned within the transverse opening of said housing means for preventing rotation of said locking piston, said locking piston including a full cylindrical surface on each end thereof, sealing means surrounding the ends of the locking piston, a longitudinally extending and inclined recess in one side of the locking piston including a camming surface complementary to and engageable with the camming surface on the wedge member, a transversely extending slot at one end of the recess in said locking piston, said slot having a semicircular cross section for enabling the wedge member to be axially moved through the slot in one end position of the locking piston, said locking piston camming surface engaging the wedge member camming surface in another end position of the locking piston for preventing movement of said wedge member when in the first position, said axially extending and inclined cam surface on said locking piston extending transversely of the locking piston a distance approximately equal to the radius of the locking piston. 
     
     
       2. Structure as set forth in claim 1, wherein the means for preventing rotation of the locking piston includes slot and pin means operable between the locking piston and housing for permitting axial movement of the locking piston transversely of the cylinder piston while preventing angular movement of the locking piston about its own axis. 
     
     
       3. Structure as set forth in claim 1, and further including mechanical return means for the locking piston. 
     
     
       4. Structure as set forth in claim 1, wherein the piston and cylinder structure is double ended and the locking structure is positioned on one end of the cylinder. 
     
     
       5. Structure as set forth in claim 1, wherein the piston and cylinder structure is single ended and the locking structure is provided on the front end of the piston and cylinder structure. 
     
     
       6. Structure as set forth in claim 1, wherein the cam surfaces are at a locking angle with respect to the directional movement of the cylinder piston. 
     
     
       7. Structure as set forth in claim 1, wherein the means for preventing rotation of the wedge member includes key and keyway means operable between the wedge member and housing for permitting axial movement of the wedge member with the piston rod while preventing angular movement of the wedge member about the axis of the piston rod. 
     
     
       8. Structure as set forth in claim 1, and further including means operable between the cylinder and cylinder piston for preventing relative rotation therebetween. 
     
     
       9. Structure as set forth in claim 8, wherein the means operable between the cylinder and cylinder piston for preventing relative rotation therebetween comprises an elongated rod, the opposite ends of which are secured against movement relative to the cylinder piston, which elongated rod extends through the cylinder piston, and sealing means for sealing between the cylinder piston and rod. 
     
     
       10. Structure as set forth in claim 1, and further including means for separately extending the cylinder piston and then locking the cylinder piston in an extended position and for subsequently separately unlocking the cylinder piston and retracting the cylinder piston. 
     
     
       11. Structure as set forth in claim 1 and further including means for extending the cylinder piston and then automatically locking the cylinder piston in an extended position and for subsequently unlocking the cylinder piston and then automatically retracting the cylinder piston.